1. Field of the Invention
The present invention relates to a ball screw device, and more particularly to a ball screw device including a preload structure or device for allowing the roller or ball bearing elements to be suitably attached or mounted or secured or engaged into the ball nut and for allowing the ball nut to be easily and quickly assembled and engaged onto the ball screw and for allowing the roller or ball bearing elements to be suitably and smoothly moved through the endless ball guiding passage of the ball screw device.
2. Description of the Prior Art
Typical ball screw devices comprise a ball nut threaded or engaged onto an elongated bolt or ball screw and rotatable and movable or adjustable along the screw, one or more endless ball guiding passages formed in the ball screw device for slidably receiving the ball bearing members, and one or more ball return pipes attached onto the ball screw device for guiding the ball bearing members to smoothly and suitably move through the endless ball guiding passages of the ball screw device.
For example, U.S. Pat. No. 6,708,577 to Pizzoni et al., U.S. Pat. No. 6,752,245 to Tsukada et al., U.S. Pat. No. 6,817,260 to Liao, U.S. Pat. No. 7,278,333 to Kato et al., U.S. Pat. No. 7,350,434 to Nishimura et al., and U.S. Pat. No. 8,082,814 to Jiang et al. disclose several of the typical ball screw return systems each comprising a ball nut threaded or engaged onto an elongated bolt or ball screw and rotatable and movable or adjustable along the screw, one or more endless ball guiding passages formed in the ball screw device for slidably receiving the ball bearing members, and one or more ball return pipes engaged onto the ball nut for guiding the ball bearing members to smoothly move through the endless ball guiding passage of the ball screw and nut combination.
However, the ball bearing members may not be easily and quickly assembled and engaged into the ball nut, and may not be smoothly move through the endless ball guiding passage of the ball screw and nut combination.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional ball screw devices or combinations.